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I got a 2001 SI coupe, 5 speed with 120000kms.
Anyways....i think I got a bad oxygen sensor..
The check engine light came up. I checked the engine and the engine is there =)
I got bad fuel milage...Lost about 50-100km on a full tank
When I shift I hear this rattle coming from the engine like the car is going to die out and stall.
The exhaust fumes stinks like its full of gas.

What do you guys think?
O2 sensor?

 
Rep Power: 306

Only way to really tell is to hook the car up to a reader. It will then tell you exactly what is going on.

Autozone might have a reader you can use to see.

 
Rep Power: 564

If you even get a reading on the computer there's something probably wrong. It shouldn't show anything unless there's an issue. Some symptoms are rough idle, sloppy acceleration and sometimes stalling out at a stop.

 
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Take it from me Boss, i know what it's like to have an 02sensor go bad. The car will have a hard time accelerating, it will stall at lights, and it will smell bad. That's what happened to my car but it wasn't the sensors. It was the wires for me. But in your case, sounds like a sensor gone bad.

 
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First post here, so Howdy! Just bought a 97 EX that is acting very much like the above-mentioned problems. Occasional miss at red lights. Slightly erratic idling, inconsistent acceleration, exhaust that smells funny So thanks for the assist. I guess I am going to do a pretty thorough tune up soon. Not too bad of a deal since I only spent 12oo bucks on the car. 88k on drivetrain . 180k on chassis

-Rob

 
Rep Power: 263

LOLL

 
Rep Power: 292

I am also having problems with my o2 Sensor. Symptoms are rough idle that surges slighty, inconsistent acceleration, and maybe bad gas mileage.

 
Rep Power: 0

Wow...my msg from 2004.
Anyways...
I have the same prob as Nameless at this moment.
Been having it for like a 3 months now. Reason being, I know something is up but not throwing CEL, so I dunno...

 
Rep Power: 0

I got my emissions test done again, second time within a year, and my car is almost failing.

The mechanic said my car is throwing away way too much un-burned gas.

My mechanic checked my plugs before, and he said there's not enough air in the mixture, he blamed my dirty air filter. I've replaced the filter and I'm still having the issue.

I've lost a lot of mileage, but the acceleration is still pretty good.

I have a check engine light that goes on and off, on and off. When I was able to check it, it was bitching out the exhaust or something. The solution online was to just take my car for a test drive. I never ended up doing it because it didn't really look like a solution to anything, but I'll attempt it once again.

I'm starting to think it's the o2 sensor since I was told it should be replaced every 80km or something. I have about 128,000km's on my 2001 civic now. I really don't know what else it could be.

 
Rep Power: 812

could be the cat converter. bad o2 sensor will trigger the check engine light. and even then a bad sensor will not really affect how the car drives. its just slower to react and you may lose a few mpg.

 
Rep Power: 388

ODB2 scanner FTW

 
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I have a 99 Civic EX coupe automatic it's my beater but I have a check engine light on as well I think I have a wiring problem wanted to know where was your wiring problem at. My brother-in-law tested it it wasnt reading my second downstream O2 sensor wasn't working (heater) part. This is the second brand new sensor I got now I'm thinking wiring on the plug.

 
Rep Power: 367

his reply was in 2004, so don't think he will be responding to you - a "few" years ago

 
Rep Power: 518

Move the post to a fresh thread?

 
Rep Power: 367

no

he specifically asked that member, by quoting him

I am just telling him that member might not be around anymore to respond to him

 
Rep Power: 0

Huh???The o2 sensor will dramatically affect how the car drives.It tells the pcm where,when and how much to enrich the fuel.I tells it also where to idle.In return the pcm tells the trans when to shift and which gear to shift to.20 years ago my civic(still my civic)stalled,died shifted crazy,one day turtles out ran me.The next day it ran like super Honda on coke.Changed iacv.TDC sensor.Cam sensor.TPS.Changed range sensor trans output sensor.Speed sensor.Fixed NOTHING.Because the Honda guys told me...o2 sensor won't affect how it runs.After lots of shop manual reading,on design & purpose of o2 sensors..I replaced them.Now it idles,runs and shifts perfectly again.

 
Rep Power: 367

gearbox have not been around for almost a decade now. no point in quoting him.
Anyway, mine just loses MPG gradually when it comes close to its life.
If yours caused that many issues, you did not took care of it in the early stages...